Alternative fulcrum hand tool



Feb. 1, 1966 w. s. MILLER 3,232,152

ALTERNATIVE FULCRUM HAND TOOL Original Filed Nov. 24, 1961 lllllll INVENTOR. IVf/VD'ZZ S. M/ZZZA? United States Patent O 3,232,152 ALTERNATEVE FULCRUM HAND TQGL WendellS. Miller, 1341 (iomstock Ave, Los Angeles, Calif. Continuation of application Ser. No..154,6016, Nov. 24, 1961. lhis application. Oct. 26,1964, Ser. No. 407,620 2 Claims. (Cl. 81-343) This application is a continuation of my prior application, Serial Number 154,606, filed November 24, 1961, now abandoned.

This invention relates to improved alternative fulcrum hand toois, particularly to pliers such as those disclosed in my prior Patent 2,906,155. Such pliers consist of twopivotally interconnected elongated members having jaw portions atone end and handle portions at their opposite ends for actuating the jaws. The pivotal interconnections consist of two alternatively operable fu crums providing difierent' mechanical advantage to the jaws upon movement of the handles. Where the term jaw is used in this application, it is contemplated these jaws may be either gripping elements for tightly holding a work piece or cutting elements for cutting the work piece.

The device described and illustrated herein is shown in the general configuration of a pair of pliers, that is to say, the two pivotal ly interconnected numbers bearing the handles and jaws are shown to cross each other ata point between the hand grips and the jaws. The fulcrum element, about which operation in the high mechanical advantage mode is eifected, also lies betweenthe hand grips and the jaws. From the following description, .it may readily be appreciated that these two features are not of themselves aspects of the invention described. It is immaterial where the members themselves cross each other, whether between the grip and jaw portions or to either side of both of these portions, itbeing well within the skill of the artisan to construct appropriate cantilevered structures connecting the jaw and hand grip portions should a particular use arise for a tool requiring such construction Further, it is not of importance for the present purpose whether the high mechanical advantage fulcrum means be located between the hand grip and jaw portion, or whether such fulcrum lie on the opposite side of the jaw portion from the hand grip area. The criterion of importance of evaluating this aspect of the structure described are that the high mechanical advantage fulcrum means shall lie closer to the side of the jaw portion than to the. hand grip portion; and that the. hand grip portion shall be so connected to the jaw portions of their corresponding members that actuation of the hand grip members.

toward each other, as by squeezing between cooperative portions of the'hand, will produce a corresponding actuation of the. jaw members toward each other with amechanical advantage greater than one. A conventional nutcrackeris an example of such a hand tool having. jaw portions. between the high mechanical fulcrum and the hand grip areas.

The general object of the invention is to provide an improved'type of tool of this general character in which a fulcrum providing lower mechanical advantage to the jaws is disposed between the handles of the tool and within the compass ofthe' hand grip upon the tool whereby the tool may be more readily adapted to singlehand operation.

Another object of the invention is to provide a tool of this general character adapted to be rapidly opened and palm of the hand will tend to close the jaw portion of the hand and rapidly closed upon the work piece by a squeezing of another portion of the hand. In particular, while the tool is engaged on the fulcrum of low mechanical advantage, a pressure between the thumb and forefinger of the hand will tend to open the jaw portions, whereas a pressure between the little finger and palm of the hand will tend to close the jaw por tions. When the tool has been closed upon the work piece, a general squeezing by the entire hand will exert force with a high mechanical advantage upon the work piece with no portion of the hand opposing this effect.

A further object of the invention is to provide in a tool of this general character means for shortening the required range of hand motion during the operation of the tool upon work pieces of different size and resiliency.

A further object of the invention is to provide a structure which is inherently sturdier and more compact thanprevious tools of this character having the same capabilities of jaw motion.

The above and other features and objects of the present invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings of which:

FIG. 1 is a side view of a pair of pliers constructed in accordance with the invention showing the pliers in their fully opened position.

FIG. 2 is a similar view of the pliers illustrated in FIG. 1 showing them in their closed position.

FIG. 3 is an enlarged fragmentary section taken along the line 33 of FIG. 2.

FIG. 4 is a fragmentary section taken along the line 4-4 of FIG. 3.

In the drawings, tool 10 includes twoelongated rigid metal members 11 and 12, which have first handle ends- 13 and 14 adapted to be actuated toward and away from each other, and second, jaw ends 15 and 16 for grippinga work piece 17 in response to actuation of handle ends. 113. The jaws 15 and 16 of course may be provided with the usual irregularities or teeth 18, for assuring effective gripping of the work piece, or cutting edges for cutting a work piece. The two-handle ends at 113- are so relatively positioned as to be receivable within the hand of the user to be manually actuated toward andaway from each other as in the manner of conventional pliers. They are preferably provided with widened hand", grip 1'3 and 14, to enable aiirm manual grip to be takencomfortably.

Member 12 rigidly carries a pivotpin 19; which preferably extends directly transversely of members ll and 12' and is rigidly fixed to member 12. A portion of pin 19 projects transversely beyond member 12 and is removably received within a slot 20, formed in member 11'. A portion 12-2, of pin 19 projects entirely through slot: 20 and provides a bearing surface for retaining spring: 23. Pin 19 is provided with a terminal cap 21 of larger diameter than slot 20 serving to retainmember 11 and 12 in operable proximity toOneanother.

Slot 20 has an end portion 22,which curves in a direction. away from the jaw end 15' of part 11 and which forms a partial cylindrical bearing surface at the end of slot 20 acting as a cam for engagement with pin 19 as a cam follower to produce relatively longitudinal motion' of members 11 and 12 upon relatively transverse motion of their respective handle portions 13' and 14; Retainingspring 23 is carried upon a pin 111, fixed to member 11.

transversely thereto. One end 123, of spring 23 is fixed relative to member 11 and a portion 125, of spring 23 is coiled about pin 111 to provide a bending moment upon the free end of spring 23 tending to confine pin 19 in the extreme end 32, of slot 20. The fixed end 123 of spring 23 may typically be inserted in a hole 124, in member 111 provided for the purpose. In addition to its turned end 22, slot 21) has a portion 26, extending arcuately about essentially the location of a secondary pivot part 25, which is carried by member 11 near its jaw end and which will be discussed in greater detail at a later point. Upon movement of pin 19 from the end 22 of slot 20 towards its opposite end, the spring 23 is yieldingly deflected as to the position of FIG. 2.

Member 12 has near its jaw end 16, a laterally enlarged portion 27, which carries an arcuate series of teeth 28, facing essentially toward the jaw end of member 12 and centered about the axis of pin 19. The previously mentioned pivot part 25, carried by member 11 has a series of similar teeth 29, which are engageable with teeth 28 upon the above mentioned longitudinal shifting movement of member 11 relative member 12 and which act to provide a fulcrum for the high mechanical advantage actuation of jaws 15 and 16 of parts 11 and 12 when pin 19 is engaged in the arcuate portion of slot 21?. Pivot part 25, may be typically formed as an integral lug or projection on member 11 and may have a side shoulder engageable at 30 with an end projection 31, on portion 27 of member 12 to limit the relative separation of jaws 15 and 16 at the FIG. 1 position. Also pivot part 25 may carry a portion 125, projecting to a position overlying the tooth portion 28 of part 12 to assist in retaining parts 11 and 12 against one another as exhibited in FIG. 3. As long as pin 19 is at end 32 of slot 20 and teeth 29 and 28 are not engaged, members 11 and 12 can pivot freely about pin 19.

The foregoing structure may now be considered conventional, the improvement disclosed herein being contained in the relative disposition of the pivot structure comprising pin 19 and slot 21) with respect to the other elements of the device. The hand grip portion of the pliers may be considered to lie between the jawward ends 112, of the handles 13 and 14 and the terminal ends 113, of these handles as disclosed in FIGS. 1 and 2. The fulcrum defined by the low mechanical advantage pivot structure comprising pin 19, the pocket of slot 20 at '32, and retaining spring 23, is medially disposed within the hand grip portion of the handles of tool it a To describe the operation of the device, assume that it is desired to grip a work piece 17, between jaws 15 and 16 f tool 10. In order to perform this operation the user first places part 17 between the jaws and then commences to manually actuate handle elements 13 and 14 relatively together at their terminal end 113. This portion of the operation of the tool requires a very small amount of force since there is no resistance to the motion of the jaws. It is accomplished by a. squeezing motion between the little finger and palm of the hand of the operator along the general arcuate line of action indicated by AA. When the jaw portions 15 and 16 make contact with the work piece 17, further relative rotation of members =11 and 12 about pivot pin 19 is resisted and the operator then exerts the full squeezing power of the hand along the general line of action BB camming pivot pin 19 away from the terminal portion 32 of slot 26 into the arcuate portion 26 thereof. This camm-ing action simultaneously engages teeth 28 and 29 at the jaw end of the tool, bringing into play the secondary or high mechanical advantage fulcrum. Continued exertion of force along the line of action BB imparts the mechanically augmented force to the work piece 17 by the jaws 15 and 16.

When it is desired to release the force upon the work piece and open the jaws of the pliers, the pressure of the hands along with the line of action BB is relaxed and the spring 23 urges the pin 19 back along the slot 20 and into the curved portion 22 where it comes to rest against the extreme end portion 32 longitudinally camming members 11 and 12 as to disengage teeth 28 and 29 and reestablish pin 19 as the low mechanical advantage fulcrum. This portion of the motion of the handles may be assisted or, at the loss of one function of the device, accomplished solely by hand mot-ion of gripping the handles of the pliers with the little linger as is customary with conventional implements. However, when pin 19) has been returned to its position at 32, spring 23 no longer efiects any urging of part 12 relative to part 11, but rather acts as a detent and further motion tending to open the jaws of tool 11! is accomplished by squeezing the handle portions 13 and 14 along the line of action 0-0 of FIG. 1 betwen the thumb and forefinger of the optrators hand. Thus while the low mechanical advantage fulcrum of tool 10 is engaged, a very rapid and delicate manipulation of the jaw opening may be affected by the squeezing of different portions of the hand grip without the necessity of reliance on any relative pulling motion to be accomplished by the hand of the operator. Such pulling motion, while possible and customary for the operation of conventional plier tools while opening the jaws of the tool, is inconvenient, ineflicient and generally unsatisfactory. It is usually accomplished by curling one or more fingers of the hand about the handles of the pliers 'or by the provision of completely looped handles against which the m-ands may exert an outward pressure.

It is apparent that the specific double fulcrum operation mechanism described herein has its equivalents such as those disclosed in my prior patent cited above and it is intended that this invention may be applied to any double fulcrum tool, however, actuated.

Thus given a double fulcrum tool of conventional construction having alternately engageable fulcrum means for providing high and low mechanical advantage to jaws from hand grip areas, this invention provides the imrprovemen-t enabling the compass of the tool to be rapidly changed when engaged in its low mechanical advantage mode by the alternate squeezing of diverse portions of the hand. The means described enabled this function to be accomplished while simultaneously permitting the entirety of the hand, without change of position, to exert its full force upon the work piece when the high mechanical advantage fulcrum is engaged. Fro-m this description, it is apparent that not only the nutcracker configuration mentioned above, but also other conventional hand tools, may be adapted to take advantage of the principle taught by the application. In particular, the direction of motion of the jaw'against the work piece is not material as is well known by reference to conventional tubing-in stretchers and piston-ring expan-ders, wherein upon actuation of the handles of such tools toward each other about a high mechanical advantage fulcrum the jaws exert outward pressure against their respective work pieces. The adaptation of such tools according to the teachings herein are apparent to those skilled in the art and require only that the two rigid members do not cross each other at the high mechanical fulcrum.

I claim:

1. A hand tool comprising two elongated members having hand (grip portions at one end thereof, said hand .grip portions being actuatable by one hand,

first pivot means connecting said members at a location medial of said hand grip portions, jaws on said elongated members on the other end thereof,

said elongated members have overlapping transverse members, said first pivot means comprising a pin on one of said transverse members and located medial of said hand grip portions,

cam means on the other of said transverse members,

said pin engaging said cam means,

second pivot means located closer to said jaws than said first pivot means and actuable sequentially of said first pivot means.

2. A hand tool as recited in claim 1 wherein said second pivot means comprise a series of teeth on one of said elongated members and a pivot part on the other of said elongated members,

said pivot part having teeth engageable with said series of teeth when said cam means has been actuated in response to actuation of said hand grip portion, and out of engagement at other times,

said second pivot means being operative alternatively of said first pivot means upon engagement of said first pivot means.

References Cited by the Examiner FOREIGN PATENTS 10/1953 Austria.

WILLIAM FELDMAN, Primary Examiner.

MILTON S. MEHR, Examiner. 

1. A HAND TOOL COMPRISING TWO ELONGATED MEMBERS HAVING HAND GRIP PORTIONS AT ONE END THEREOF, SAID HAND GRIP PORTIONS BEING ACTUATABLE BY ONE HAND, FIRST PIVOT MEANS CONNECTING SAID MEMBERS AT A LOCATION MEDIAL OF SAID HAND GRIP PORTIONS, JAWS ON SAID ELONGATED MEMBERS ON THE OTHER END THEREOF, SAID ELONGATED MEMBERS HAVE OVERLAPPING TRANSVERSE MEMBERS, SAID FIRST PIVOT MEANS COMPRISING A PIN ON ONE SIDE OF SAID TRANSVERSE MEMBERS AND LOCATED MEDIAL OF SAID HAND GRIP PROTIONS, CAM MEANS ON THE OTHER OF SAID TRANSVERSE MEMBERS, SAID PIN ENGAGING SAID CAM MEANS, SECOND PIVOT MEANS LOCATED CLOSER TO SAID JAWS THAN SAID FIRST PIVOT MEANS AND ACTUABLE SEQUENTIALLY OF SAID FIRST PIVOT MEANS. 